View Single Post
  #1   Spotlight this post!  
Unread 25-03-2010, 04:12
pproc pproc is offline
Registered User
no team
 
Join Date: Mar 2010
Location: india
Posts: 4
pproc is an unknown quantity at this point
Re: Palm Pilot LCD screen pinout in progress

I have a similar Palm Pilot type PDA screen - the circuit board is silkscreened with a Picvue PC1721WE legend. Purchased from excesssolutions.com

This also has a 20 pin connector, but appears to be different from the Picvue PC0919WE07 described in the Olimex page.

PC1721WE seems to have a built in EL driver with a H826 driver IC (compared to the H830 in the Olimex schematic which looks like it is external to the LCD module). PC1721WE also seems to have a built in contrast voltage supply circuit.

Playing with a multimeter, I am reasonably certain that pins 20...17 are data bus, 13 & 7 are GND, 4..1 are the touchscreen interface pins.

Pins 14,11,8 and 5 are also connected to the lcd glass traces - i assume they are control pins - clock, enable etc.

There is also a pad on the board that seems to be a testpad for the contrast voltage.

Just by supplying power 3.3V to the H830 EL driver VDD pin, and 3.3V to pin 11 and pin 14, I can see the display flash, and then a contrasty line on top, and the testpad voltage is 21.5V. When I set pin 11 to GND, the screen flashes, and then blanks, the test pad voltage is 15V. From this i assume there is no need for me to supply an external 18V VHH drive as per the PC0919WE interface in the Olimex schematic.

Any pointers to similar LCD interfaces / pinouts / datasheets would be much appreciated !! I got two of these for $5 each, would be great if I can get them up and running.
Reply With Quote